1. Field of the Invention
The present invention relates to an optical subassembly, in particular, the invention relates to a mechanism to assemble the optical subassembly on a circuit board.
2. Background Arts
A Japanese Patent Application published as JP-2008-028309A has disclosed one type of an optical subassembly with an optical device and an optical coupling unit. The optical device may be a semiconductor laser diode (hereafter called as LD), and/or a photodiode (hereafter called as PD). The optical subassembly disclosed therein is electrically connected to a circuit board of the host system by lead pins extending from a housing of the optical subassembly, and physically fixed to the circuit board, or a case of the host system, by screws.
An optical module or an optical sub-assembly following the multi-source agreement of the XLMD-MSA provides a housing having screw holes to fix the module/sub-assembly to a case of, for instance, the CFP optical transceiver. A plurality of lead pins extends from the housing of the optical module/sub-assembly to be electrically connected with the circuit board.
In order to secure the signal quality in a high frequency region exceeding, for instance, 10 GHz, the optical module/sub-assembly may provide electrical connectors, or often called as RF connectors, specific to transmit such high frequency signals in addition to the lead pins. However, when the housing of the optical module/sub-assembly is not aligned with the circuit board, mechanical stresses may be arisen in the electrical connector by fixing the housing of the optical module/sub-assembly to the case or the circuit board of an optical transceiver, which may degrade the quality of the signal transmitting therethrough.